In electric power transmission and distribution networks, fault current conditions may occur. A fault current condition is an abrupt surge in the current flowing through the network caused by a fault or a short circuit in the network. Causes of a fault may include lightning striking the network, and downing and grounding of transmission power lines due to severe weather or falling trees. When a fault occurs, a large load appears instantaneously. In response, the network delivers a large amount of current (i.e., overcurrent) to this load or, in the case, the fault. This surge or fault current condition is undesirable and may damage the network or equipment connected to the network. In particular, the network and the equipment connected thereto may burn or, in some cases, explode.
One system used to limit a fault current and to protect power equipment from damage caused by a fault current is a superconducting fault current limiter (SCFCL) system. Generally, an SCFCL system comprises a superconducting circuit that exhibits almost zero resistivity below a critical temperature level TC, a critical magnetic field level HC, and a critical current level IC. If at least one of these critical level conditions is exceeded, the circuit quenches and exhibits resistivity.
During normal operation, the superconducting circuit of the SCFCL system is maintained below the critical level conditions of TC, HC, and IC. During a fault, one or more of the aforementioned critical level conditions is exceeded. Instantaneously, the superconducting circuit in the SCFCL system is quenched and resistance surges, which in turn limits transmission of the fault current and protects the network and associated equipment from the overload. Following some time delay and after the fault current is cleared, the superconducting circuit returns to normal operation wherein none of the critical level conditions are exceeded and current is again transmitted through the network and the SCFCL system.
Conductors, typically in the form of a flat wire or conductive tape, are typically used to transmit electrical energy or signals within the SCFCL system. For example, within the SCFCL system, a superconducting circuit may be disposed between two external terminals. This superconducting circuit carries current between these two terminals. During normal operation, this superconducting circuit may allow hundreds of amps to pass. In the event of a fault, almost no current passes, and a large voltage difference exists between the two terminals. The voltage difference may determine the length of superconducting tape that is disposed within the SCFCL system. The operational current may determine how many superconducting tapes are used in parallel to deliver the desired current. Therefore, often a plurality of conductive tapes is used to transmit the electrical energy. These superconducting tapes are assembled within a device that may include a plurality of connectors, each of which holds a corresponding conductive tape. These connectors may be stacked on top of one another to form a stack.
Conductive tapes may expand due to changes in temperature, and also may vibrate due to magnetic fields generated by current flowing through the conductive tapes. Therefore, these connectors typically have a minimal spacing between each other to minimize the likelihood of the conductive tapes touching each other, during normal or fault conditions. Such contact, even if minimal, may result in electrical and/or mechanical interference, which may lead to decreased longevity and reliability of the conductive tapes.
The number of connectors and the minimal spacing between connectors are factors in determining the overall size of the SCFCL system. Therefore, it would be beneficial to minimize the connecting system employed in a SCFCL system. A smaller form factor connecting system may reduce the overall size of the SCFCL system for a given operating specification. Additionally, within a given volume, higher voltage/current operation would be possible.